Home Heat Pump Guide

Heat Pump Grant Timeline: How Long Does It Take?

One of the most practical questions homeowners ask about the Boiler Upgrade Scheme is: how long does the whole process actually take? From your first enquiry to having a working heat pump, the typical timeline is four to eight weeks — though it can be faster or slower depending on your circumstances.

This guide breaks down every stage of the BUS grant process with realistic timeframes, explains what can cause delays, and gives you practical tips for keeping the process moving as quickly as possible.

The Full Timeline: Stage by Stage

Here is the typical timeline for a BUS grant-funded heat pump installation in England or Wales:

Stage 1: Getting Quotes — 1 to 2 Weeks

The process starts when you request quotes from MCS-certified installers. You should aim to get at least three quotes to compare prices and recommendations.

  • Day 1-3: Submit quote requests and receive initial responses from installers
  • Day 3-10: Installers visit your property to carry out a site survey. They will assess your home's heat loss, check the suitability for a heat pump, inspect your radiators and pipework, and identify the best location for the outdoor unit
  • Day 7-14: Receive written quotes with system specifications, costs, and grant details

During busier periods (spring and early summer are peak times for heat pump enquiries), it may take longer to arrange site surveys. Planning ahead helps — do not wait until your boiler has broken down to start the process.

Stage 2: Choosing Your Installer and EPC — 1 to 2 Weeks

Once you have your quotes, take time to compare them carefully. Look beyond price — consider the installer's experience, the system they recommend, their warranty terms, and their reviews from previous customers.

  • Compare quotes: 2-3 days
  • Get an EPC (if needed): 3-7 days. If you do not have a valid EPC, you will need to arrange one. An energy assessor will visit your home and issue the certificate, which typically takes a few days to come through. See our EPC requirements guide
  • Address EPC recommendations: Variable. If your EPC recommends loft or cavity wall insulation, you will need to have these installed before proceeding. This can add several weeks to the timeline
  • Accept quote and sign contract: 1-2 days

Stage 3: BUS Grant Application — 2 to 4 Weeks

This is the stage most people ask about, and it is also the stage you have least control over. Your MCS-certified installer submits the BUS grant application to Ofgem on your behalf. You do not need to do anything except provide your property details and consent.

  • Application submission: Your installer submits the application through the Ofgem portal, including your property details, EPC reference, system specifications, and quoted costs
  • Ofgem processing: Typically takes 2 to 4 weeks. During busier periods, it may take slightly longer
  • Approval notification: Both you and your installer receive confirmation that the grant has been approved

What Happens During Ofgem Processing?

Ofgem checks several things when processing your application:

  • Your property's EPC is valid and meets the requirements
  • The property has not already received a BUS grant
  • Your installer is MCS-certified
  • The proposed system meets the scheme's technical requirements
  • The property is in England or Wales
  • The property is not a new build

If anything is missing or incorrect, Ofgem may request additional information, which can add a few days to the process.

Stage 4: Installation — 2 to 5 Days

Once the grant is approved, your installer will schedule the installation. The actual installation typically takes two to five days, depending on the complexity:

  • Day 1: Outdoor unit installation — preparing the base, placing the heat pump, and connecting refrigerant pipework
  • Day 2: Indoor work — installing the hot water cylinder, connecting pipework to your existing heating system, and any necessary electrical work
  • Day 3: Completing connections, installing controls and thermostat, decommissioning the old boiler
  • Day 4-5 (if needed): Radiator upgrades, additional pipework modifications, or more complex installations
  • Final day: Commissioning, testing, and handover — your installer demonstrates how to use the system

For a detailed look at what happens during installation, see our installation guide.

Stage 5: Grant Payment and Completion — 1 to 2 Weeks

After installation, your installer completes the MCS paperwork and notifies Ofgem that the installation is finished. The grant payment process then follows:

  • Installer submits completion certificate: Within a few days of installation
  • Ofgem processes payment: The £7,500 grant is paid directly to the installer, typically within 1 to 2 weeks
  • You pay the balance: You pay your installer the difference between the total cost and the grant

In practice, most installers will agree payment terms with you at the time of installation rather than waiting for Ofgem's payment. This means you typically pay your share when the installation is complete, without needing to wait for Ofgem.

Total Timeline Summary

  • Getting quotes: 1-2 weeks
  • Choosing installer and EPC: 1-2 weeks
  • BUS grant application and approval: 2-4 weeks
  • Installation: 2-5 days
  • Grant payment: 1-2 weeks
  • Total typical timeline: 4-8 weeks from first enquiry to working heat pump

What Can Cause Delays?

Several factors can extend the timeline beyond the typical four to eight weeks:

EPC Issues

If your EPC recommends loft or cavity wall insulation, you must address these before the BUS grant can be approved. Getting insulation installed can add two to six weeks to the timeline, depending on the type of insulation and the availability of contractors.

Installer Availability

During busy periods — particularly spring and early autumn — MCS-certified installers may have waiting lists of several weeks. Starting the process early and being flexible with dates helps avoid this bottleneck.

Equipment Lead Times

Some heat pump models may have longer lead times than others. If your installer recommends a specific system that is not in stock, you may need to wait for delivery. Discuss lead times when choosing your system.

Planning Permission

Most domestic heat pump installations fall under permitted development rights and do not need planning permission. However, if your property is listed, in a conservation area, or if the installation does not meet permitted development criteria, you may need to apply for planning permission. This can add six to twelve weeks to the timeline.

Ofgem Processing Backlogs

Occasionally, Ofgem experiences backlogs in processing applications, particularly after policy changes or at the end of financial quarters. During these periods, approval may take four to six weeks rather than the typical two to four.

How to Speed Up the Process

Here are practical steps to keep the process moving as quickly as possible:

  1. Get your EPC done first. If you do not have a valid EPC, arrange one before contacting installers. If it recommends loft or cavity wall insulation, get these done before starting the heat pump process
  2. Request quotes early. Do not wait for an emergency. Start getting quotes as soon as you begin thinking about a heat pump
  3. Respond to installers promptly. When they ask for information or access to your property, respond quickly to avoid delays
  4. Be flexible with installation dates. The more flexible you are, the sooner your installer can schedule the work
  5. Choose a common heat pump model. Popular models from major manufacturers are more likely to be in stock
  6. Avoid peak season if possible. Late autumn and winter are typically quieter periods for installers, so you may get faster service

Timeline for Scotland

If you are in Scotland, the process is similar but uses Home Energy Scotland (HES) instead of the BUS grant. The HES process includes:

  • Initial contact with HES: Call 0808 808 2282 or apply online
  • Home assessment: HES arranges a home energy assessment (1-3 weeks)
  • Recommendation and grant/loan offer: 1-2 weeks after assessment
  • Getting installer quotes: 1-2 weeks
  • Installation: 2-5 days
  • Total: Typically 6-10 weeks

The Scottish process can take slightly longer because it includes a more comprehensive home assessment stage, but the end result is usually more generous funding.

What Happens If the Grant Is Rejected?

BUS grant rejections are uncommon if your installer has checked the eligibility criteria beforehand, but they can happen. Common reasons for rejection include:

  • EPC recommendations for loft or cavity wall insulation not addressed
  • Property is a new build
  • Property has already received a BUS grant
  • Installer's MCS certification has lapsed
  • Technical details of the proposed system do not meet scheme requirements

If your application is rejected, your installer can usually resolve the issue and resubmit. This adds two to four weeks to the timeline but rarely results in a permanent refusal.

Frequently Asked Questions

How long does the BUS grant application take?

The application itself is submitted by your installer and takes about 30 minutes. Ofgem typically processes and approves applications within two to four weeks.

Can I start the installation before the grant is approved?

No. You must wait for Ofgem to approve the grant before installation begins. Installing before approval means you will not receive the grant.

How long does the actual installation take?

Typically two to five days, depending on the complexity of the installation. Simple replacements in properties with existing radiator systems take less time than installations requiring significant pipework or radiator changes.

What is the quickest possible timeline?

If you already have a valid EPC, choose an installer quickly, the grant is approved promptly, and the installer has immediate availability, the entire process could be completed in three to four weeks. This is rare but possible.

What is the longest the process might take?

If you need insulation work, planning permission, or face installer backlogs, the process could take three to six months. The most common cause of extended timelines is addressing EPC insulation recommendations.

Is there a deadline for the BUS grant?

The BUS grant scheme runs until March 2028. There is no need to rush, but given that budgets are allocated annually, it is sensible not to delay unnecessarily. See our grant amounts guide for current details.

Ready to get started? The sooner you begin, the sooner you will have a working heat pump. Get free quotes from MCS-certified installers today, or use our heat pump calculator to estimate your costs. You can also read our complete grants guide to make sure you are accessing every pound of funding available.